The 'hippie' movement, it is generally believed, and agreed upon by most scholars, had its earliest origins in the 19th century 'Fabian' and 'Bohemian' movements, which advocated 'free living' and sexual and moral licence. Later on, during the period 1890s to 1908-1910, a German youth movement 'Der Wandervogel', also sprang up which left some effects on the later movement.
However, in real, practical terms, the movement, as we know it, certainly took off in the USA , in the late 1950s and early 1960s. The 'Beat Generation' or 'beatniks' of the 50s gave way to the 'hippies', and one prime figure at this time, was the poet Allen Ginsberg, originally one of the famous 'Beat poets'- and Ginsberg is supposed to have got together with a group of other famous people, such as Bob Dylan, Timothy Leary and etc, to 'experiment' with LSD and other drugs, which were to become an integral part of the hippie movement.
Until 1965, there was actually NO CLEAR DISTINCTION between the terms 'beatnik' and 'hippie' and it is also claimed that the Hippies began to emerge as a separate entity, with their distinct psychedelic clothes and all, sometime around 1966-67. Other people/groups and incidents, also played an important role, around this time, in defining some other aspects of Hippie culture - e.g 'the Merry Pranksters' group, the Red Dog Saloon, the Civil Rights Movement and the anti-Vietnam war protests, a growing Western interest (thanks to the Beatles in the UK) in mystical Oriental religions and cults etc etc.
Thus, 'hippie-ism' cannot claim one, fixed 'inventor' or 'founder'-- if anything, in the 1950s-60s, it was basically the 'Beat Generation' which evolved into the Hippies.